High intensity light-emitting diode luminaire assembly

ABSTRACT

A lighting assembly that includes a heatsink housing, a plurality of light emitting diode (LED) modules, and a power supply disposed within a power supply casing, wherein the power supply is for providing power to the LED modules. Each LED module includes a plurality of LEDs and is thermally connected to the heatsink housing. The power supply casing includes a structure for cooling the power supply.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and is a continuation of U.S. patentapplication Ser. No. 15/492,342, filed Apr. 20, 2017 which claimspriority to and is a continuation of U.S. patent application Ser. No.14/364,803, filed Jun. 12, 2014, now U.S. Pat. No. 9,657,930, which is anational stage application of, and claims priority to InternationalPatent Application No. PCT/US2012/069442, filed Dec. 13, 2012, which inturn claims priority to (i) U.S. Provisional Patent Application No.61/570,072, filed Dec. 13, 2011 and (ii) U.S. Provisional PatentApplication No. 61/712,226, filed Oct. 10, 2012, each of which isincorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to high intensity light-emitting diode(LED) array technology. The invention further relates high intensity LEDluminaires and high intensity LED luminaire (HILL) assemblies andmethods for making them.

BACKGROUND OF THE INVENTION

High intensity light-emitting diode (LED) array technology is currentlyused to provide lighting in a wide range of applications in which theuser needs high intensity illumination.

One drawback of existing high intensity LED luminaire (HILL) assemblies(also known as high intensity LED light fixtures or high intensity LEDlight fittings) is poor thermal management, which drastically reducesproduct lifespan. Extended operation of LEDs at temperaturessignificantly above ambient is not possible with existing HILL designs,yet such assemblies throw off large amounts of heat which are notadequately dispersed.

Another drawback of existing luminaire or HILL assemblies is their“throw-away” design. Lack of in-field serviceability leads to disposalof the entire luminaire assembly rather than replacing its electronics.This wastes resources, since many components that are still serviceable.Furthermore, existing HILLs lack balanced current control and can beprone to “thermal runaway,” which in turn can cause premature failure ofthe luminaire and shorten its lifespan.

Another drawback of existing HILLs is off-angle glare: when an overheadluminaire is operating, users at ground level see spikes of lightintensity emitted by the luminaire, rather than consistent and evenillumination over the entire illuminated field.

Citation or identification of any reference in Section 2, or in anyother section of this application, shall not be considered an admissionthat such reference is available as prior art to the present invention.

SUMMARY OF THE INVENTION

In a scenario, a lighting assembly may include a heatsink housing, aplurality of light emitting diode (LED) modules, and a power supplydisposed within a power supply casing, wherein the power supply is forproviding power to the LED modules. Each LED module may include aplurality of LEDs and is thermally connected to the heatsink housing.The power supply casing may include a structure for cooling the powersupply. Optionally, the lighting modules are thermally insulated fromthe power supply. Additionally, the power supply casing may not beincluded in the heatsink housing.

In certain embodiments, the heatsink housing may include a plurality offins that face towards the power supply, and the LEDs of the LED modulesface away from the power supply. In at least one embodiment, the LEDsmay be removable from the lighting assembly. The structure for coolingthe power supply may include a plurality of fins disposed on the powersupply casing.

In one or more scenarios, the lighting assembly may also include asecondary lens element that is positioned over the LED modules.Optionally, the secondary lens element may include a plurality of lensesand/or a sealing lens that is received by the heatsink housing and thatrenders the lighting assembly waterproof.

The lighting assembly may also include a circuit board upon which theplurality of LEDs are mounted and that includes driver circuitry fordriving the plurality of LEDs. Each LED module may include a pluralityof parallel strings of LEDs and the driver circuitry may be configuredto provide a constant current to the at least one LED module so thatvoltage delivered to each string of LEDs is automatically adjusted ifany LED in the string fails. The driver circuitry may also include pulsewidth modulation circuitry configured to enable dimming of the pluralityof LEDs by varying pulse width modulation. Alternatively and/oradditionally, the driver circuitry may further include feedbackcircuitry for balancing power input to each of a plurality of LEDstrings. Optionally, each of the LEDs may be positioned on a front sideof the circuit board adjacent a via element that extends through thecircuit board to a via backing formed of a thermally conductive materialto provide the thermal connection of the LEDs to the heatsink housing.

In certain embodiments, the power supply comprises at least one DC powersupply. The DC power supply may include a DC-DC converter for convertingincoming voltage from about 390 V to 12 V DC operating voltage.

In an embodiment, the lighting assembly may also include a mountingbracket configured for multi-angle positioning of the lighting assembly.

In another scenario, a lighting assembly may include a heatsink housing,a plurality of light emitting diode (LED) modules, a secondary lenselement that is positioned over the LED modules, and a power supplydisposed within a power supply casing, wherein the power supply is forproviding power to the LED modules. Each LED module may include aplurality of LEDs and is thermally connected to the heatsink housing.The power supply casing may also include structure for cooling the powersupply.

Optionally, the secondary lens element may include a plurality of lensesand/or a sealing lens that is received by the heatsink housing and thatrenders the lighting assembly waterproof.

Optionally, each of the LEDs may be positioned on a front side of acircuit board, included in the lighting assembly, adjacent a via elementthat extends through the circuit board to a via backing formed of athermally conductive material to provide the thermal connection of theLEDs to the heatsink housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described herein with reference to theaccompanying drawings, in which similar reference characters denotesimilar elements throughout the several views. It is to be understoodthat in some instances, various aspects of the invention may be shownexaggerated, enlarged, exploded, or incomplete to facilitate anunderstanding of the invention.

FIG. 1 is a perspective drawing of a first embodiment of a HILL assemblyin accordance with the present invention.

FIG. 2 is an exploded perspective view of the embodiment shown in FIG. 1.

FIG. 3 is a plan view of a lens element comprising a plurality ofconcavo-convex lenses (CCLs) for use in the first embodiment for floodlighting.

FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 3 .

FIG. 5 is a plan view of a LED array for use in the first embodiment.

FIG. 6 is a side view of the LED array shown in FIG. 5 .

FIG. 7 is a perspective view of an outer frosted dome lens for use in alow bay application of the first embodiment.

FIG. 8 an exploded perspective view and an assembled view of a LEDmodule (also referred to herein as LED replacement module) in accordancewith the present invention comprising a LED array, thermal gaskets,interface plate, a current balancing controller FR4 circuit card, and apower supply connector.

FIGS. 9 and 10 respectively are an end view and a perspective view of aheatsink housing as shown in FIGS. 1 and 2 .

FIG. 11 is a side view of the HILL assembly shown in FIGS. 1 and 2further comprising an ambient light sensor and an occupancy sensor.

FIGS. 12 through 14 are perspective views showing various mountingconfigurations that can be achieved with the first HILL assemblyembodiment shown in FIG. 1 .

FIGS. 15 and 16 are perspective views from above and below,respectively, of a second embodiment of a HILL assembly in accordancewith the present invention.

FIG. 16 a is an enlarged view of the portion of FIG. 16 shown in circle16 a showing the joiner with mating edges.

FIG. 17 is a view like that shown in FIG. 15 showing a portion of onebank of LED lamp assembly cutaway.

FIG. 18 is an enlarged view of the portion of FIG. 17 shown in circle18.

FIG. 19 is an end view of a finned heatsink.

FIG. 20 is a first exploded perspective view from above of the secondembodiment shown in FIG. 15 .

FIG. 21 is a second exploded perspective view from below of the secondembodiment shown in FIG. 15 .

FIG. 22 is a plan view of an idealized 16-lens module in accordance withthe present invention.

FIG. 23 is a perspective view of the idealized lens module shown in FIG.22 .

FIG. 24 is a plan view of a modular circuit board assembly in accordancewith the present invention.

FIG. 25 is an isometric view of an exemplary multiple-module assembly ofHILLs in accordance with the second embodiment shown in FIG. 21 .

FIG. 26 is an end view of an exemplary single-module HILL in accordancewith the second embodiment shown in FIG. 21 .

FIG. 27 is a plan view of a first exemplary embodiment of a 16-lensmodular subassembly in accordance with the present invention.

FIG. 28 is a plan view of a second exemplary embodiment of a 16-lensmodular subassembly in accordance with the present invention.

FIG. 29 is a plan view of the reverse side of either of the first andsecond embodiments shown in FIGS. 27 and 28 .

FIGS. 30 a, 30 b, 30 c, 30 c (1), and FIG. 31 are electrical drawings ofLED driver circuitry in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

A high intensity LED luminaire (HILL) assembly (also known in the art asa high intensity LED light fixture, high intensity LED light fitting orLED luminaire) is provided. The HILL assembly can be used indoors oroutdoors, and in wet, damp or dry environments. In various embodiments,the HILL can be powered by a universal AC (90-480 VAC, 47-440 Hz) or aDC (12-480 VDC) electrical supply. The operational temperature range forthe HILL is from about −40° C. to about +80° C. In a preferredembodiment, the HILL assembly comprises a heatsink, referred to hereinas a “heatsink housing,” that serves the dual purpose of functioning asthe housing for the HILL assembly and as the heatsink for the HILLassembly.

A HILL assembly in accordance with a first embodiment of the presentinvention can comprise a LED module that is replaceable (or exchangeableor interchangeable) having a plurality of LEDs disposed in a LED array;an array of concavo-convex lenses (CCLs, also known in the art as“concave meniscus” lenses) disposed adjacent to the LED array; a thermalinsulator; a heatsink housing; a power supply and associated circuitry;and a circuit board for controlling the LED array by thermal viatechnology. The LEDs are mounted directly on the circuit board. A firstembodiment HILL assembly is well adapted for use, for example, as afloodlight, spotlight, worklight, or hand-held flashlight.

In a second embodiment, the LEDs are arranged in a circular orrectilinear modular array. Modules in the modular array may be gangedtogether into larger units for use in, for example, overhead roomlighting, desk lighting, street lighting, or stadium lighting. Lensescan be adjustable to vary the size and shape of the field illuminated byeach LED. In certain embodiment, the power supply driving circuitry canbe positioned or mounted directly on the circuit board.

In various embodiments, the HILL assembly can be used for lightingindoor or outdoor areas or for flood lighting. It can be used in highbay or low bay applications. It will be apparent to the skilled artisanthat the HILL assembly has many uses for illuminating commercial orindustrial settings, but can also be used in residential settings. Thecommercial or industrial settings in which the HILL assembly can be usedcan include, but are not limited to, offices, manufacturing facilities,warehouses, parking garages, ball parks, stadiums, and storage areas.

For clarity of disclosure, and not by way of limitation, the detaileddescription of the invention is divided into the subsections set forthbelow.

5.1. HIGH INTENSITY LED LUMINAIRE (HILL) ASSEMBLY—FIRST EMBODIMENT

Referring now to FIGS. 1-16 , a first embodiment 10 of a HILL assemblyin accordance with the present invention comprises at least a secondarylens element 12 comprising a plurality of CCLs 14; a LED module 16,comprising a plurality of LEDs 18 equal in number to the number of CCLs14, positioned in a first LED array 20; a heatsink (also referred toherein as a heatsink housing) 22; and a power supply 24 disposed withinheatsink housing 22. Embodiment 10 further comprises a first O-ring 28;first and second thermal gaskets 30; an interface plate 32; a secondO-ring 34 for sealing heatsink housing 22 at the front end; a thirdO-ring 36 for sealing heatsink housing 22 at the rear end; a back plate38; a junction box 40; and sealing gaskets 42.

Lens Element

HILL assembly 10 comprises a single secondary lens element 12 (FIGS. 2-3) with one or more CCLs 14 integrated into the lens element. Lenselement 12 is also referred to herein as a secondary lens, because theprimary lens is a part of the actual LED chip itself. Lens element 12 ispreferably made of injection molded plastic, and more preferably, a hightemperature acrylic. Other materials, such as borosilicate glass or anoptical grade polyycarbonate, can also be used. In first embodiment 10,lens element 12 can comprise a plurality of CCLs 14 (in this embodiment,36 in number, see FIGS. 1-3 ) integrated into a singular lens element.As shown in FIG. 4 , the concave lens surface 25 of each CCL 14, incombination with the convex lens surface 26 of the CCL, creates widedispersion optics. After assembly of embodiment 10, each LED 18 ispositioned within the concavity of one of the concave surfaces 24 whenthe lens element 12 is positioned on or attached to the LED array 20(FIGS. 4-6 ). In some embodiments, the outer edges 19 of lens element 12(FIGS. 3-4 ) can be frosted to reduce off-angle glare.

FIG. 7 shows a perspective view of a different embodiment of a secondarylens element 12A for use in a low bay application. FIG. 7 contains oneor more CCLs 14 integrated into the lens element. Secondary lens element12A comprises a hexagonal lens 14A that is used to make a more uniformdistribution of light on the ground for individual LEDs in LED array 20.

LED Array

HILL assembly 10 comprises a LED array 20 comprising a plurality of LEDs18 positioned in the array (see FIGS. 2, 5 and 6 ). Any suitable LED orplurality of LEDs known in the art can be used in the LED array 20. Eachof the LED elements 18 comprises a primary lens.

HILL assembly 10 also comprises one or more securing screws 44 (FIGS. 5and 8 ) or any other suitable securing fastener, adhesive, clamp, springpin, or tensioning device that secures the LED array 20 in place. Infirst embodiment 10, a plurality of screws 44 (a plurality of 10 screwsin the embodiment illustrated in FIGS. 5 and 8 ) are used to secure thevarious components of the HILL assembly, including the LED array 20, tointerface plate 32 (see FIGS. 2 and 8 ). In a preferred embodiment, theLED array 20 is a component of a LED module 16 ((also referred to hereinas a LED “replaceable” or “replacement” module; FIGS. 2 and 8 ), whichcan be removed in the field (i.e., where it is installed) throughremoval of the securing screws 44. This enables the LED module 16comprising the LED array 20 to be exchanged, interchanged or replaced asdesired by the user.

The LED array 20 comprises a circuit board or card 46 (FIG. 5 ) forcontrolling the LED array. Preferably, the circuit card 46 is a FR4circuit board, which is a low-cost fiberglass reinforced epoxy laminateknown in the art that is flame retardant. Although metal clad circuitcards known in the art, such as metal core printed circuit boards(MCPCB) can also be used, their use is less preferred, since they have amuch greater cost than FR4 circuit boards. In a preferred embodiment,circuit board 46 employs FR4 with thermal via technology to provide alow cost circuit board that performs thermally equivalent or better thana metal clad circuit board. Incorporating thermal vias into board designis well known in the art, and mitigates thermal issues by lowering thethermal resistance of the circuit card itself, (see, e.g., Cree, Inc.(2010), Optimizing PCB Thermal Performance for Cree® XLamp® LEDs,Technical Article CLD-AP37 REV 1, Cree, Inc., 4600 Silicon Drive,Durham, N.C. 27703, available athttp://www.cree.com/products/pdf/XLamp_PCB_Thermal.pdf (last visitedDec. 13, 2011); IPC 7093: Design and Assembly Process Implementation forBottom Termination SMT Components ISBN 1-580986-90-0, available forpurchase at http://www.ipc.org, Table of Contents available free athttp://www.ipc.org/TOC/IPC-7093.pdf (last visited Dec. 13, 2011)).

The LED array 20 preferably comprises parallel strings of LEDs 18, whicharrangement confers several advantages. First, this allows for gracefuldegradation as the array ages. For example, in an embodiment with fourparallel strings of LEDs, two of the four strings can fail and the lightwill still provide the rated lumen output. Second, the LED array doesnot experience hot spots that reduce LED lifespan. By balancing thecurrent through each string to be within 1% of one another, the LEDarray runs at a uniform temperature. Hot spots form on a LED array whendesigns use parallel strings without current balancing. As the arraypowers up, most of the current travels down the string with the lowestvoltage potential. Since not all LEDs are created equal, this willhappen. When a single string uses more current than the other strings,those LEDs heat up faster than the others. As the string heats up, theLEDs' voltage potential drops, which in turn causes the LEDs to consumemore current from the cooler strings. This effect is known in the art as“thermal runaway” and causes LED arrays to fail prematurely.

In contrast to existing HILL assemblies that have LED arrays eitherpermanently bonded to the heatsink housing 22 or connected through useof a thermal paste, a HILL assembly 10 in accordance with the presentinvention comprises a LED module 18 comprising a LED array 20 that is aremovable and/or exchangeable component and not a permanently installedcomponent of the HILL assembly. The LED array 20 is preferably acomponent of a LED module 18, but can also be a separate, exchangeablecomponent within the scope of the present invention. Preferably, the LEDmodule 18 comprises pre-installed thermal gaskets or pads 30, so thatthe end user does not have to apply any thermal paste (which is atedious, delicate process) when exchanging or replacing the LED module.When installed, the LED module 18 is thermally in contact with heatsinkhousing 22, which is a high-efficiency finned, thermal radiator, so thatheat is dispersed from the module via the heatsink. The LED module 18 ismounted on and removed from the heatsink housing 22 via securing screws48 (FIG. 2 ) or other suitable fasteners known in the art, which can,for example, be threadedly received in bores 50 (FIG. 9 ). The LEDmodule 18 is operably connected electrically through preferably one(preferably keyed) power supply connector (or single connection plug) 52(FIG. 8 ) that is attached to interface plate 32 via screws 54 (FIG. 8). In another embodiment, a T-slot connection can be used for operablyconnecting LED modules.

Heatsink or Heatsink Housing

HILL assembly 10 can comprise a heatsink that also functions as aheatsink housing 22 (FIGS. 2, 9 and 10 ) that is an open-die, finnedmetal extrusion formed preferably of an aluminum alloy. It will berecognized by the skilled artisan that other designs known in the artcan be used, including but not limited to die castings and splitextrusions. The open-die finned extrusion design is preferably used, asit offers a good combination of low price and high performance. Priorart luminaires typically have heatsink bodies that comprise two halvesthat are bolted or bonded together to form the heatsink. By contrast,the open-die heatsink is one piece, which has numerous benefits (i.e.low cost of assembly, sealing potential, etc.).

Thermal extrusion of the heatsink housing 22 can be used for efficientthermal management. The finned design generates a large surface areaover a small length, effectively pulling heat away from the LEDcomponents. Additionally, the open cavity 56 of the heatsink housingserves as the housing for internal components, comprising at least onepower supply 24. In various embodiments, the open cavity 56 can house aplurality of power supplies.

Heatsink housing 22 comprises a groove 23 (FIG. 9 ) surrounding theopenings of cavity 56 at each end of the housing. An O-ring 34, 36(e.g., an elastomeric O-ring) is disposed in each groove 23 for sealingcavity 56 by engaging interface plate 32 and back plate 38, respectively(FIG. 2 ).

Heatsink housing 22 can also comprise fins 62 (FIGS. 2, 9 and 10 ). Incertain embodiments, the fins 62 are capable of multi-angle positioning.In another embodiment, the fins can be longitudinal. In otherembodiments, the fins can be arranged transversely or radially.

In certain embodiments, the heatsink housing is waterproof and/orsubmersible.

In another embodiment, the mounting bracket 60 is capable of multi-anglepositioning.

Components for Positioning and Reducing Off-Angle Glare

Prior art luminaires reduce off-angle glare through the addition of aspun metal or refractive plastic shield, which is an additional cost.These shields are relatively large and totally block off-angle glare butdo not block the dispersion of the light source, thus wasting off-anglelight output of the device.

The secondary lens 12 of the first embodiment of the HILL assembly 10can comprise a frosted lip 19 (FIG. 4 ) that can be integral to thesecondary lens element 12 that serves to partially attenuate the lightsource as seen from an angle. The cost of integrating this frosted lip19 into the secondary lens is negligible and can be done, for example,as part of the injection molding process for forming lens element 12.

In another embodiment, the HILL assembly can comprise a mounting bracket60 (FIG. 2 ) or any other mounting system known in the art for mountingor securing a luminaire or other lighting element. Other suitablemounting brackets for luminaires are well known in the art. In specificembodiments, the mounting bracket or system can swivel, pivot or providemulti-positioning of the HILL assembly.

As a single fixture, HILL assembly 10 supports free hanging, ceiling,wall, stanchion, and pendant mounting and can optionally comprise asensor for sensing an environmental parameter of interest, such as anambient light sensor 64 and/or an occupancy sensor 66 (FIG. 11 ). Suchsensors are well known in the art and commercially available. As will beapparent to the skilled practitioner, such optional components can beinstalled in a number of suitable configurations for sensing anenvironmental parameter of interest.

For example, in one embodiment, the ambient light sensor 64 has theability to generate a user-defined light output profile, as describedfurther below, based on user defined schedules or personnel detectionand ambient light measuring. Light output is adjusted based on currentlyavailable light, to save the user energy by not duplicating light.

In another embodiment, the occupancy sensor 66 turns the light on/offbased on user-defined time intervals.

Because HILL assembly 10 has a brick-like design that supportsmulti-module ganging or stacking, a single HILL assembly 10 can beganged with other like fixtures to make, e.g., a spot light 68 (FIG. 12), arena/stadium light 70 (FIG. 14 ), or a linear fixture for widerangle lighting 72 (FIG. 13 ). By employing a modular design for HILLassembly 10 and using industry standard open interfaces, the design isflexible and upgradeable.

Because HILL assembly 10 has instant on/off capabilities, it can be usedin power management schemes to generate user-defined light outputprofiles based on user-defined schedules or personnel detection andambient light measuring. HILL assembly 10 can be used to generate lightoutput based on detection of currently available light (e.g., withoptional ambient light sensor 66) and to save the user energy by notduplicating light. In addition, in embodiments in which an occupancysensor installed, HILL assembly 10 can detect, and be used in, powermanagement schemes that switch the light on or off based on user-definedtime intervals.

In one embodiment, HILL assembly 10 can predict or indicate how muchtime is left on the light until the lumen output decays below the L70level (70% of lumen output at time=0 hours).

In another embodiment, HILL assembly 10 can comprise a programmabletimer or timing function. Such programmable timers or timing functionsare well known in the art.

Table 1 presents ranges of dimensions for various elements of HILLassembly 10, as well as the dimensions of one preferred embodiment. Itwill be apparent to the skilled artisan that other suitable dimensionscan be easily determined for the components of the HILL listed below, aswell as for other components described herein.

TABLE 1 Length (in) Width (in) Height (in) Part Preferred Max MinPreferred Max Min Preferred Max Min Secondary 7 24 0.5 7 24 0.5 0.88 60.1 Lens 12 LED Array 6.15 24 0.25 6.15 48 0.25 0.06 0.25 0.01 20 LED 724 0.25 7 48 0.25 0.95 6 0.1 Module16 Heatsink 7 14 0.5 7 14 0.5 11 240.1 22 Mounting 8.17 48 0 7.45 48 0 2 6 0 Bracket 60

5.2. HIGH INTENSITY LED LUMINAIRE (HILL) ASSEMBLY—SECOND EMBODIMENT

A HILL assembly is also provided that is based on a modular design. Invarious embodiments, the HILL assembly can comprise modular lensingprovided by, e.g., a lens matrix, a plurality of LED modules or modularLED arrays, joiner brackets that allow for modularity and custom angularpositioning of light output, modular heatsink housing(s) and high powermodular circuits (that can operate, for example, at high temperatures).

The modular lensing allows for mixing and matching of distributionpatterns, which can provide precise, including but not limited tocustom, optical controls.

The LED modules or modular LED arrays can have a shared cover designthat allows for stacking or joining of multiple modules without the needfor fasteners. An advantage of this design is that it does not interferewith the function of the heatsink. The design can allow heat to bepulled with convectional heat transfer.

The cover can also allow for modules to be attached by a joiner bracketas separate units with the cover holding them together. In a specificembodiment, a power supply can be positioned in the middle of such amodular arrangement.

Referring now to FIGS. 15-31 , a second embodiment 110 of a HILLassembly in accordance with the present invention is shown. FIGS. 15 and16 are perspective views from above and below, respectively, of thissecond embodiment.

HILL assembly 110 comprises a linear, one-piece, finned, metal heatsinkhousing 122 formed preferably by extrusion of an aluminum alloy (seeFIGS. 18-21 ). Heatsink housing 122 forms the structural frame ofassembly 110 and comprises several features that permit attachment ofessentially all the other components of assembly 110, as describedbelow.

The HILL assembly can be thermally optimized for heat transfer throughgable and ridge vent thermal optimization.

A plurality of formed channels 124 receive a plurality of screws 126that secure end cap 128 (also referred to herein as gable end cap) toheatsink 122, as shown in FIGS. 19 and 20 . End cap 128 preferablyincludes at least one opening 129 (FIG. 20 ) as an intake forconvectional cooling air for the fins in heatsink 122. The aspect ratioof the end cap 128 allows for a vortex to drive heat from the finnedregion of heatsink housing 122 and allows for driving the LEDS at highercurrents than in the prior art to yield higher light output, asdescribed in more detail below. The heatsink housing 122 can have, forexample, two slits cut to increase airflow, therefore reducing thetemperature of the HILL assembly.

A plurality of mating features, e.g., T-slots 130 can receive matingfeatures (e.g., T-mating features) 132 extending from LED module (alsoreferred to herein as LED subassembly) 134, as shown in FIGS. 18, 21,and 26 , providing secure mounting and thermal connection of LED module134 to heatsink housing 122. The use of T-slots increases the efficiencyof the HILL assembly, and allows, for example, for mixing LED arraystogether on a common track.

Opposed lips 136 receive opposed edges of a sealing lens 137,protectively enclosing LED module 134, and in certain embodiments,rendering it waterproof. In one embodiment, the sealing lens can be madeof a transparent thermoplastic such as poly(methyl methacrylate) (PMMA).

A joiner (or “joiner bracket”) 140 is also provided. Outer beaded fins138 can receive mating edges of the joiner 140 in either a single-moduleHILL assembly, as shown in FIG. 26 , or optionally in a multiple-moduleHILL assembly. In one embodiment, this joiner is configured to allow forangular positioning to direct light output to meet specific needs.

In one embodiment, a HILL assembly module 142 can comprise a heatsinkhousing 122, a LED module 134, and a sealing lens 137. Such a HILLassembly module 142 may be employed singly or ganged in a wide varietyof configurations determined by lighting requirements and space. Forexample, a single module assembly can form a desk lamp or under-cabinetkitchen lamp; a double module assembly such as is shown in FIGS. 15 and16 , can be useful as an overhead shoplight or for general overheadillumination by ceiling installation; and larger still assemblies, suchas 16-module assembly 144 shown in FIG. 25 , can be useful for wide areafloodlighting as in stadiums or arenas. Referring to FIG. 20 , to makethe HILL assembly modular, a joiner 140 is used to fasten or connectheatsink housings together.

A bracket arm 148 is connected to either the endcap or the joiner 140 oneach side of the HILL assembly. The bracket arms 148 can contain orenclose the wiring for the power supply 150 and connect to each side ofthe power supply casing 146. A bracket cover 149 can cover the bracketarm. Inside the casing 146, at least one DC power supply 150, and in aspecific embodiment, two DC power supplies 150, can be attached. Thepower supply casing permits cooling of the power supply 150.

Referring now to FIGS. 21 through 24 , in a presently-preferredembodiment, each HILL assembly module 142 comprises two LED modules 134disposed end-to-end (shown for clarity without sealing lens 137). Toassemble HILL assembly module 142, the T-features 132 of each LED moduleare simply entered into the mating T-slots 130 in heatsink housing 122.

The HILL assembly can have on-board “string” control and currentsharing, i.e., constant on-time current control. Referring now to FIGS.24-31 a-c, each LED module 134 can comprise a circuit board 160 uponwhich are mounted 64 LEDs 162 arranged in four rows of 16 LEDs each.Preferably, the LEDs 162 in each row are wired in series and the rows164, also referred to herein as “strings”, are wired in parallel.Circuitry 166 provides constant current to the LEDs such that if one LEDfails, the circuit auto-adjusts to provide more current to the remainingLEDs, thus restoring total light output. HILL assembly module 142includes a power supply 150 (FIG. 17 ) that includes a DC-DC converterthat can downstep any incoming voltage from up to 390 v down to 12 voperating voltage. Such a low voltage step-down converter enables highefficiency of the HILL assembly.

Circuitry 166 for driving the LEDs 162 is mounted directly on circuitboard 160, allowing the constant current feature just described, and isconnected to first and second multi-prong connectors 168 a, 168 b atopposite ends of circuit board 160, allowing connection to adjacentmodules 134.

Because circuitry 166 is designed specifically for these applicationsand is not bought off-the-shelf, circuitry 166 can be formed, in oneembodiment, as an integral element of circuit board 160. This results ingreatly increased electrical efficiency of 100 lumens/watt, whereasprior art systems typically operate in the range of 80 lumens/watt.Because the light output is greater, there is less waste electricalenergy and less heat generated, e.g., thermal density is reduced. Thispermits LEDs 162 to run continuously at only 80° C. or lower, whereasprior art systems being driven at such high light outputs must run atgreater than 100° C. and are therefore prone to thermal runaway andfailure.

Because circuitry 166 can operate at constant current, the power flowingto the individual LED strings 164 is balanced, preventing thermalrunaway. Referring to FIG. 30 , LED driver 180 (LM3464) includes afeedback loop that continuously balances power feed to minimizetemperature on each LED string 164.

The HILL assembly can have optimized thermal transfer from the LED arrayto the heatsink housing through a thermally conductive material. In oneembodiment, to disperse and equalize the heat generated by LEDs 162,each LED can be positioned on the front side of circuit board 160adjacent at least one via element (not visible) extending throughcircuit board 160 into connection with a via backing (not visible) oncircuit board 160 formed of a thermally conductive material such ascopper, beryllium oxide, aluminum, FR4, or graphene.

A secondary lens 170, similar to secondary lens 12 in first embodiment10, is disposed over each LED 162. Lenses 170 preferably are formed inmodular lens matrices (also referred to herein as lens subassemblies)172 of lenses, e.g., a 4×4 array of 16 lenses (although other suitablelens matrices can be determined by the skilled artisan) arranged in asquare matrix that can be screwed down on top of its respective LEDs, asshown in FIGS. 22-24 .

To vary the size and shape of the field illuminated by each LED, theindividual lenses 170 may be varied in capability, as shown in modularlens matrices (also referred to herein as lens subassemblies) 172 a and172 b in FIGS. 27 and 30 , respectively. A plurality of lensescomprising at least two different types of LED lenses can be used.Preferably, LED lenses standardized by the Illumination EngineersSociety of America (IESA) are employed. For example, a module 172 a, 172b may comprise a plurality of Type 5 (“round”) lenses 174, a pluralityof Type 3 (“butterfly”) lenses 176, and a plurality of Type 2 (“skinny”)lenses 178. It will be apparent to the skilled artisan than manydifferent combinations of lenses can be made. Thus because of thismodular matrix lensing, a HILL assembly is provided wherein differentIESA standard lens types can be provided within the same light fixture.

The lenses in the modular lens matrix can be rotated or adjusted toachieve different lighting configurations with the same HILL assembly.

In one embodiment, each HILL assembly module 142 is preferably about 12inches long and the 64 LEDs 164 are powered to emit 64,000 lumens oflight. Other suitable module lengths (in the range, for example, of 6-12inches, 12-24 inches, 24-35 inches) will be readily apparent the skilledartisan. Modules can be used to create any desired configuration ofmodules, e.g., 1×2, 1×3 m 1×4 m 2×2, 2×3, 3×3, 3×4, 4×4 etc.

A currently preferred embodiment, as shown in FIG. 21 , provides a24-inch heatsink housing comprising two HILL assembly modules 142. Anadvantage of this design is that modular lighting can be constructed inmodular sections (e.g., 12 inch sections) that can be customized in manydifferent configurations.

Referring now to FIGS. 24, 30 a, 30 b, 30 c, 30 c(1), and 31, drivercircuitry 166 allows variation of the voltage across the LED strings toa minimal value required to maintain a constant current through all fourstrings. This ability to vary the output voltage to a minimal valuedecreases the power loss of those strings that require less voltageacross the LEDs. This arrangement also allows the flexibility to changethe number of LEDs per string as well as the number of LED strings (1 to4) without the need to purchase a new constant current supply as inprior art arrangement. In the present invention, this function uses asingle constant voltage power supply.

In typical prior art applications, a constant current supply is utilizedwithout the use of circuitry to vary the output voltage, meaning thatthe constant current power supply's output voltage just climbs towhatever voltage the highest LED string needs. The other strings thatrequire less voltage need to dissipate the excess power created by thehigh voltage setting which leads to inefficient and less reliabledesigns. In the prior art, if the number of LEDs were to change, a newversion of constant current power supply would need to be selected.

In certain embodiments, the LEDs 162 can be dimmable by pulse widthmodulation (PWM). Thus, the HILL assembly can also comprise pulse widthmodulation (PWM) circuitry. The PWM circuitry converts the 0-10V analogsignal to a PWM signal.

A method for maintaining a constant LED color temperature (CCT) and/or acolor rendering index (CRI) in a lighting assembly (e.g., a HILLassembly) is also provided. The method comprises the steps of usingconstant drive current, thereby decreasing photon emissions; and varyingpulse width modulation (PWM). These steps together provide overalldimming of the light output at frequencies higher than are currently onthe market. Constant CCT and CRI are maintained while dimming from 100%to 0% because of this pulse width modulation (PWM).

With PWM come the benefits of maintaining a constant LED colortemperature (CCT) and color rendering index (CRI). Preferably, PWM isconducted at higher frequencies in the range of 10 kHz to 20 kHz tocomply with high definition cameras/filming. The higher frequency rangealso allows elimination of any audible noise in applications wherenecessary to do so.

In a specific embodiment, pulse width modulation (PWM) can be used at afrequency of 10 GHz to 24 GHz as a method to dim the light output. Thisfrequency range allows the light output to be dimmed at an optimalfrequency that is ideal for not interfering with other visibleactivities, including, but not limited to high definition televisionrecording and broadcasting. Using PWM to dim the light output maintainsthe Color Rendering Index (CRI) and Color Temperature (CCT) of the LED.

In certain embodiments, the HILL comprises a 0-10V dimmer circuit. Thisallows the advantage of using a commercially available 0-10V dimmerswitch, but such a switch does not provide a pulse width modulation(PWM) output.

In one embodiment, the HILL assembly is preferably IEC6929 annexcompliant (on board) for 0-10V operation.

In a preferred embodiment, a HILL assembly comprises both a 0-10V dimmercircuit and a pulse width modulation (PWM) circuit. Positioning thecircuitry adjacent to, or in association with the LEDs is particularlypreferred. 2) there is constant voltage 3) pulse width modulation.

5.3. METHODS FOR MAKING HILL ASSEMBLIES

The HILL assemblies disclosed herein can be made using conventionalmanufacturing techniques known in the art. The construction of theelements of the HILL assemblies will be readily apparent to the skilledpractitioner. For example, heatsinks can be produced by conventionalextrusion techniques. Power supplies and circuit boards are also madeusing conventional methods. No special manufacturing techniques ormanufacturing environments are needed to produce the assemblies.

5.4. INDEX FOR NUMBERED ELEMENTS

-   -   10 HILL assembly, first embodiment    -   12 lens (or secondary lens) element    -   14 CCLs    -   16 LED module    -   18 LEDs    -   19 frosted lip    -   20 first LED array    -   22 heatsink housing    -   23 groove surrounding the openings of cavity 56    -   24 power supply    -   25 concave lens surface of each CCL 14    -   26 convex lens surface    -   28 first O-ring    -   30 first and second thermal gaskets    -   32 interface plate    -   34 second O-ring for sealing heatsink housing 22 at the front        end    -   36 third O-ring for sealing heatsink housing 22 at the rear end        back plate    -   38 back plate    -   40 junction box    -   42 sealing gaskets    -   44 securing screws    -   46 circuit board or card    -   48 securing screws    -   50 bores    -   52 power supply connector    -   54 screws    -   56 open cavity    -   60 mounting bracket    -   62 fins of heatsink housing 22    -   64 ambient light sensor    -   66 occupancy sensor    -   68 spot light    -   70 arena/stadium light    -   72 linear fixture for wider angle lighting    -   110 HILL assembly, second embodiment    -   122 linear, one-piece, finned, metal heatsink housing    -   124 channels    -   126 screws    -   128 end plate    -   129 opening in end plate    -   130 T-slots    -   132 mating T-features    -   134 LED module    -   136 opposed lips    -   137 sealing lens    -   138 outer beaded fins    -   140 joiner 140    -   142 HILL assembly module    -   144 16-module assembly    -   146 power supply casing    -   148 bracket arm    -   149 bracket cover    -   150 power supply    -   151 electrical access cover    -   152 power supply wires    -   154 openings to allow venting of heated air from the fins    -   156 bottom panel    -   160 circuit board    -   162 LEDs    -   166 driver circuitry for driving the LEDs    -   168 a, 168 b first and second multi-prong connectors    -   170 secondary lens    -   172, 172 a and 172 b lens matrix    -   174 round lenses    -   176 butterfly lenses    -   178 skinny lenses    -   180 LED driver

The present invention is not to be limited in scope by the specificembodiments described herein. Indeed, various modifications of theinvention in addition to those described herein will become apparent tothose skilled in the art from the foregoing description. Suchmodifications are intended to fall within the scope of the appendedclaims.

While embodiments of the present disclosure have been particularly shownand described with reference to certain examples and features, it willbe understood by one skilled in the art that various changes in detailmay be effected therein without departing from the spirit and scope ofthe present disclosure as defined by claims that can be supported by thewritten description and drawings. Further, where exemplary embodimentsare described with reference to a certain number of elements it will beunderstood that the exemplary embodiments can be practiced utilizingeither less than or more than the certain number of elements.

All references cited herein are incorporated herein by reference intheir entirety and for all purposes to the same extent as if eachindividual publication, patent or patent application was specificallyand individually indicated to be incorporated by reference in itsentirety for all purposes.

The citation of any publication is for its disclosure prior to thefiling date and should not be construed as an admission that the presentinvention is not entitled to antedate such publication by virtue ofprior invention.

The invention claimed is:
 1. A lighting assembly comprising: a heatsinkhousing; a plurality of light emitting diode (LED) modules, each ofwhich comprises a plurality of LEDs, and each of which is thermallyconnected to the heatsink housing; and a power supply disposed within apower supply casing, wherein the power supply is for providing power tothe LED modules, and the power supply casing comprises a structure forcooling the power supply, wherein the heatsink housing is configured formulti-angular positioning with respect to the power supply casingthrough a joiner bracket.
 2. The lighting assembly of claim 1, whereinthe lighting modules are thermally insulated from the power supply. 3.The lighting assembly of claim 1, wherein the power supply casing is notincluded in the heatsink housing.
 4. The lighting assembly of claim 1,wherein the heatsink housing comprises a plurality of fins that facetowards the power supply, and the LEDs of the LED modules face away fromthe power supply.
 5. The lighting assembly of claim 1, wherein the LEDmodules are removable from the lighting assembly.
 6. The lightingassembly of claim 1, further comprising a secondary lens element that ispositioned over the LED modules.
 7. The lighting assembly of claim 6,wherein the secondary lens element comprises a plurality of lenses. 8.The lighting assembly of claim 6, wherein the secondary lens elementcomprises a sealing lens that is received by the heatsink housing andthat renders the lighting assembly waterproof.
 9. The lighting assemblyof claim 1, further comprising a mounting bracket that is configured tofor multi-angle positioning of the lighting assembly.
 10. The lightingassembly of claim 1, wherein the power supply comprises at least one DCpower supply, the DC power supply comprising a DC-DC converter forconverting incoming voltage from up to about 390 V to about 12 V DCoperating voltage.
 11. The lighting assembly of claim 1, furthercomprising a circuit board upon which the plurality of LEDs are mountedand that includes driver circuitry for driving the plurality of LEDs.12. The lighting assembly of claim 11, wherein: each LED modulecomprises a plurality of parallel strings of LEDs; and the drivercircuitry is configured to provide a constant current to each LED moduleso that voltage delivered to each string of LEDs in each LED module isautomatically adjusted if any LED in the string fails.
 13. The lightingassembly of claim 11, wherein the driver circuitry further comprisesfeedback circuitry for balancing power input to the strings of LEDsincluded in each LED module.
 14. The lighting assembly of claim 11,wherein the driver circuitry further comprises pulse width modulationcircuitry configured to enable dimming of the LEDs by varying pulsewidth modulation.
 15. The lighting assembly of claim 11, wherein each ofthe LEDs is positioned on a front side of the circuit board adjacent avia element that extends through the circuit board to a via backingformed of a thermally conductive material to provide the thermalconnection of the LEDs to the heatsink housing.
 16. The lightingassembly of claim 1, wherein the structure for cooling the power supplycomprises a plurality of fins disposed on the power supply casing.
 17. Alighting assembly comprising: a heatsink housing; a plurality of lightemitting diode (LED) modules, each of which comprises a plurality ofLEDs, and each of which is thermally connected to the heatsink housing;a secondary lens element that is positioned over the LED modules; apower supply disposed within a power supply casing, wherein the powersupply is for providing power to the LED modules, and the power supplycasing comprises structure for cooling the power supply, wherein theheatsink housing is configured for multi-angular positioning withrespect to the power supply casing through a joiner bracket, and whereinthe LED modules are thermally insulated from the power supply.
 18. Thelighting assembly of claim 17 wherein the secondary lens elementcomprises a plurality of lenses.
 19. The lighting assembly of claim 17,wherein the secondary lens element comprises a sealing lens that isreceived by the heatsink housing and that renders the lighting assemblywaterproof.
 20. The lighting assembly of claim 17, further comprising: acircuit board, and wherein each of the LEDs is positioned on a frontside of the circuit board adjacent to a via element that extends throughthe circuit board to a via backing formed of a thermally conductivematerial to provide the thermal connection of the LEDs to the heatsinkhousing.